Scientists home in on a potential Anthropocene Golden Spike in new research

The international working group, which includes geologists Jan Zalasiewicz, Mark Williams and Colin Waters, from our School of Geography, Geology and the Environment and archaeologist Matt Edgeworth has, since 2009, been analysing the case for formalisation of the Anthropocene, a potential new epoch of geological time dominated by overwhelming human impact on the Earth.

The group has found that a broad range of potential physical, chemical and biological markers characterise the Anthropocene, the clearest global markers being radionuclide fallout signals from nuclear testing and changes in carbon chemistry through fossil fuel burning – these in particular show marked changes starting in the early to mid-1950s.

The group, with a number of invited scientists, has now reviewed present knowledge on where these and other markers form the clearest, sharpest, and most stable signal in strata that might be used to define the Anthropocene as a formal unit of the Geological Time Scale.

The current study, which is published in the journal Earth-Science Reviews, informs the scientific community where they should start the process of collecting and analysing continuous core samples of strata across the proposed Holocene–Anthropocene transition. The study considered a range of arguments in support of and against hosting a ‘golden spike’ in a range of potentially suitable environments across the globe. They found that Anthropocene strata are often thin – but also that they are globally distributed and may be clearly recognised by geologists.

Professor Colin Waters, who led the study, said: “This study considers those environments in which the very short history of the Anthropocene is best recorded. In addition to such traditional geological strata, we have also considered human-generated deposits, sediments accumulating in lakes, estuaries and deltas, peat bogs, cave mineral deposits and even biological hosts such as corals and trees. The presence of annual layers or growth rings within many of these provides geologically unprecedented accuracy in the placement of the primary reference marker, wherever this might be ultimately chosen.”

Scientists within the Anthropocene Working Group are working towards developing a proposal, based upon finding a ‘golden spike’, more technically known as a Global Boundary Stratotype Section and Point (GSSP). This is a reference level within recent strata somewhere in the world that will be proposed to most clearly and consistently characterise the changes as the Holocene, which represents the last 11,700 years of geological time on this planet, gave way into the Anthropocene about 65 years ago.